Linux Kernel Developer: Kees Cook

Part of the ongoing Linux development work involves hardening the kernel against attack.

Security is paramount these days for any computer system, including those running on Linux. Thus, part of the ongoing Linux development work involves hardening the kernel against attack, according to the recent Linux Kernel Development Report.

This work, according to report authors Jonathan Corbet and Greg Kroah-Hartman, involves the addition of several new technologies, many of which have their origin in the grsecurity and PaX patch sets. “New hardening features include virtually mapped kernel stacks, the use of the GCC plugin mechanism for structure-layout randomization, the hardened usercopy mechanism, and a new reference-count mechanism that detects and defuses reference-count overflows. Each of these features makes the kernel more resistant to attack,” the report states.

Kees Cook

In this series, we are highlighting some of the hard-working developers who contribute to the Linux kernel. Here, Kees Cook, Software Engineer at Google, answers a few questions about his work.

Linux Foundation: What role do you play in the community and what subsystem(s) do you work on?

Kees Cook: Recently, I organized the Kernel Self-Protection Project (KSPP), which has helped focus lots of other developers to work together to harden the kernel against attack. I’m also the maintainer of seccomp, pstore, LKDTM, and gcc-plugin subsystems, and a co-maintainer of sysctl.

Linux Foundation: What do you think the kernel community needs to work on in the upcoming year?

Cook: I think we’ve got a lot of work ahead in standardizing the definitions of syscalls (to help run-time checkers), and continuing to identify and eliminate error-prone code patterns (to avoid common flaws). Doing these kinds of tree-wide changes continues to be quite a challenge for contributors because the kernel development model tends to focus on per-subsystem development.

Linux Foundation: Why do you contribute to the Linux kernel?

Cook: I’ve always loved working with low-level software, close to the hardware boundary. I love the challenges it presents. Additionally, since Linux is used in all corners of the world, it’s hard to find a better project to contribute to that has such an impact on so many people’s lives.